Crushers are utilized in many applications for crushing hard material, such as rocks, ore, etc. One type of crusher is the gyratory crusher, which has a crushing head which is forced to gyrate inside a fixed crushing shell. A crushing chamber, into which pieces of rock are to be fed, is formed between a crushing mantle, which is supported by the crushing head, and the crushing shell. The width of the crushing chamber, often referred to as the gap or the setting of the crusher, may be adjusted by a hydraulic arrangement. During the crushing of rock, ore etc. the crusher is subjected to large load variations. Such load variations cause wear, including metal fatigue, in the crusher, and may decrease the life of the crusher.
Patent document GB 1 517 963 discloses a gyratory crusher having a hydraulic cylinder or an air cylinder for preventing overload situations. A pressure buffer is operative for accommodating sudden heavy load changes in the hydraulic system. The pressure buffer is connected to the hydraulic system and by a point of constriction provided between the cylinder and the pressure buffer.
While the pressure buffer of GB 1 517 963 may be operative for reducing the negative effects of sudden heavy load changes, it is not effective for reducing the normal load variations that cause fatigue failure in the crusher.